Recent guidelines recommend oxygen saturation (SpO(2)) levels of 90%-95% for preterm neonates on supplemental oxygen but it is difficult to discern such levels with current pulse oximetry sonifications. We tested (1) whether adding levels of tremolo to a conventional log-linear pulse oximetry sonification would improve identification of SpO(2) ranges, and (2) whether adding a beacon reference tone to conventional pulse oximetry confuses listeners about the direction of change. Participants using the Tremolo (94%) or Beacon (81%) sonifications identified SpO(2) range significantly more accurately than participants using the LogLinear sonification (52%). The Beaton sonification did not confuse participants about direction of change. The Tremolo sonification may have advantages over the Beacon sonification for monitoring SpO(2) of preterm neonates, but both must be further tested with clinicians in clinically representative scenarios, and with different levels of ambient noise and distractions. Crown Copyright (C) 2016 Published by Elsevier Ltd. All rights reserved.

The goal of this project was to determine the feasibility of non-invasively monitoring the blood gases of construction workers for carbon monoxide exposure via pulse oximetry. In particular, this study sought to understand the impact of motion artifacts caused by the worker's activities and to determine if those activities would prevent the blood gas sensor from detecting the onset of carbon monoxide poisoning. This feasibility study was conducted using a blood oxygen sensor rather than a blood carbon monoxide sensor for several reasons. First, blood gas sensors that measure blood carbon monoxide are not readily available in suitable physical form factors. Second, sensors for blood oxygen and blood carbon monoxide operate on the same physical principles and thus will be affected in the same way by worker motions. Finally, using a blood oxygen sensor allowed the study to be conducted without exposing the human subjects to carbon monoxide. A user study was conducted to determine the distribution of motion artifacts that would be created during a typical work day. By comparing that distribution to a worst-case estimate of time to impairment, the probability that helmet will adequately monitor the worker can be established. The results of the study show that the helmet will provide a measurement capable of warning the user of on setting carbon monoxide poisoning with a probability greater than 99%. / Master of Science

Pulse oximetry is used to measure heart rate (HR) and arterial oxygen saturation (SpO2) from photoplethysmographic (PPG) waveforms. PPG waveforms are highly sensitive to motion artifact (MA), limiting the implementation of pulse oximetry in mobile physiological monitoring using wearable devices. Previous studies have shown that multichannel pulse oximetry can successfully acquire diverse signal information during simple, repetitive motion, thus leading to differences in motion tolerance across channels. In this study, we introduce a multichannel forehead-mounted pulse oximeter and investigate the performance of this novel sensor under a variety of intense motion artifacts. We have developed a multichannel template-matching algorithm that chooses the channel with the least amount of motion artifact to calculate HR and SpO2 every 2 seconds. We show that for a wide variety of random motion, channels respond differently to motion, and the multichannel estimate outperforms single channel estimates in terms of motion tolerance, signal quality, and HR and SpO2 error. Based on 31 data sets of PPG waveforms corrupted by random motion, the mean relative HR error was decreased by an average of 5.6 bpm when the multichannel-switching algorithm was compared to the worst performing channel. The percentage of HR measurements with absolute errors ≤ 5 bpm during motion increased by an average of 27.8 % when the multichannel-switching algorithm was compared to the worst performing channel. Similarly, the mean relative SpO2 error was decreased by an average of 4.3 % during motion when the multichannel-switching algorithm was compared to each individual channel. The percentage of SpO2 measurements with absolute error ≤ 3 % during motion increased by an average of 40.7 % when the multichannel-switching algorithm was compared to the worst performing channel. Implementation of this multichannel algorithm in a wearable device will decrease dropouts in HR and SpO2 measurements during motion. Additionally, the differences in motion frequency introduced across channels observed in this study shows precedence for future multichannel-based algorithms that make pulse oximetry measurements more robust during a greater variety of intense motion.

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I rapporten presenteras en lågkostnads, portabel och bärbar design av ett nytt system med reflekterande teknik för pulsoximetri. Arbetet har utförts som ett projekt, inkluderande elektronikkonstruktion, mjukvaruutveckling, design av inkapsling för prototypen samt fortlöpande tester av både hård- och mjukvara under arbetets gång. Resultatet av arbetet är ett egenkonstruerat system för pulsoximetri. Med hjälp av bluetooth-teknik kan systemet kommunicera trådlöst med en PC, laptop eller mobiltelefon som stöder bluetooth 4.0. Mätvärden visas i realtid på PC/laptop/mobiltelefon. Programvaran är skriven i mbed med programspråket C++ för mikroprocessorn. Projektet kräver olika tekniska färdigheter såsom signalbehandling, programmering, kretskortskonstruktion och mikroprocessorer. Totalt sett är projektet en bra introduktion till medicintekniska enheter och en grund för elektronikingenjörer. Syftet och målet med examensarbetet har till större delen uppnåtts och vidare tester samt utveckling av produkten är möjlig. / In this report a low-cost, portable and wearable design of a new system with reflective technologyfor pulse oximetry is presented. The work has been executed as a project, including electronics construction, software development, a design of the embedding for the prototype and continuous tests of both the hardware and software during the work in progress. The result of this work is a prototype system for pulse oximetry. The system can communicate through Bluetooth wireless interface with a PC, laptop or smartphone which supports Bluetooth 4.0. The measurements are shown in real time on a PC/laptop/smartphone. The software is written in mbed with the language C++ for the microprocessor. The project demands different technical skills like signal processing, programming, electronic design and microprocessors. Over all the project is a good introduction for medical technology and a basis for electronic engineers. The purpose and goal with the thesis is considered to be reached for the most part and further testing and development of the product is possible.

O objetivo deste trabalho foi avaliar a taxa de oxigenação (%SpO2) do tecido pulpar em pacientes com tumores malignos intraoral e de orofaringe, tratados através de radioterapia (RT). As mensurações da %SpO2 foram realizadas com o oxímetro de pulso (OP), o qual gera valores relativos à quantidade de oxigênio viável circulante no tecido pulpar, o que o caracteriza como um método fisiométrico de avaliação do status da polpa dental. Foram selecionados 20 pacientes, sendo avaliados dois dentes de cada um (n=40), independente do quadrante e da área de irradiação, em quatro tempos distintos: I- antes da RT; II- no início da RT com dose de radiação entre (30Gy 35Gy); III- ao final da RT (60Gy 70Gy) e IV- depois de 4 5 meses do início do tratamento oncológico. As médias obtidas nos quatro tempos avaliados foram de 93%, 83%, 77% e 85% de SpO2, respectivamente. Através do teste t de Student (p0.01) foram encontradas diferenças estatisticamente significantes entre o Tempo I e todos os outros três tempos, o Tempo III também mostrou diferença quando comparado ao Tempo II e, não houve diferença estatística entre os Tempos II e IV. É possível concluir que as taxas de %SpO2 antes da RT são maiores do que aquelas obtidas trans e pós RT e, como os valores no Tempo IV ficam próximos aos obtidos no Tempo II, pode haver uma recondutibilidade sanguínea normal posterior a radiação ionizante. / The aim of this study was to evaluate pulp oxygenation level (%SpO2) in patients with malignant intraoral and oropharyngeal tumors treated by radiotherapy (RT). Pulp oxygenation level was measured by pulse oximetry, which shows the amount of oxygen circulating in viable pulp tissue and is a physiometric method for assessment of dental pulp status. Twenty patients were selected and two teeth of each of them (n = 40) were analyzed, regardless of the quadrant and the area irradiated, at four different times: I- before RT; IIat the beginning of RT with radiation doses between 30Gy 35Gy; III- at the end of RT (60Gy 70Gy) and IV- after 4-5 months of the beginning of the cancer treatment. Mean %SpO2 in the different times was 93%, 83%, 77% and 85%, respectively. Students t test (p0.01) showed statistically significant differences between Time I and the other three times. Time III was also different when compared to Time II, and there was no statistical difference between Times II and IV. It was concluded that %SpO2 before RT was greater than that observed during and after therapy and, as values obtained in Time IV were close to those of Time II, pulp tissue may show normal blood flow after radiation therapy.

"A wireless wearable battery-operated pulse oximeter has been developed in our laboratory for field triage applications. The wearable pulse oximeter, which uses a forehead-mounted sensor to provide arterial oxygen saturation (SpO2) and heart rate (HR) information, would enable field medics to monitor vital physiological information following critical injuries, thereby helping to prioritize life saving medical interventions. This study was undertaken to investigate if accelerometry (ACC)-based adaptive noise cancellation (ANC) is effective in minimizing SpO2 and HR errors induced during jogging to simulate certain motion artifacts expected to occur in the field. Preliminary tests confirmed that processing the motion corrupted photoplethysmographic (PPG) signals by simple Least-Mean-Square (LMS) and Recursive Least-Squares (RLS) ANC algorithms can help to improve the signal-to-noise ratio of motion-corrupted PPG signals, thereby reducing SpO2 and HR errors during jogging. The study showed also that the degree of improvement depends on filter order. In addition, we found that it would be more feasible to implement an LMS adaptive filter within an embedded microcontroller environment since the LMS algorithm requires significantly less operations."

A verificação da vitalidade pulpar depende de recursos semiotécnicos específicos, e, entre eles, os mais comumente empregados são os testes térmicos e elétrico. Tais testes apresentam limitações clínicas que interferem na análise e interpretação dos dados obtidos pelos mesmos. Os testes de sensibilidade são estímulos de origem térmica, elétrica ou mecânica aplicáveis ao dente e que são transmitidos às fibras nervosas sensitivas pulpares. Portanto, não leva em consideração a atividade circulatória do tecido pulpar e as condições de oxigenação, que são os reais indicadores da vitalidade do tecido. Nos casos de traumatismos dentários, por diversos fatores, a resposta pulpar se torna ainda mais difícil de obter. Assim, faz-se necessário avaliar o comportamento fisiológico pulpar através de testes denominados fisiométricos, destacando-se nesta área a oximetria de pulso, que é um método não invasivo e objetivo para determinação da saturação de oxigênio e taxa de pulso de um determinado tecido. Este estudo procurou estabelecer parâmetros para a utilização do oxímetro de pulso como teste de vitalidade pulpar, avaliando, comparativamente, os níveis de saturação de oxigênio obtidos do dedo indicador, de dentes controle positivo e de dentes permanentes traumatizados dos mesmos pacientes. Os dentes traumatizados apresentavam resposta negativa ao teste de sensibilidade pulpar com gás refrigerante e ausência de outro sinal ou sintoma indicativo de necrose pulpar. Os resultados mostraram que não houve diferença estatisticamente significante comparando-se as taxas de oxigenação dos dentes traumatizados nos três tempos (inicial, 30 e 60 dias) e que houve correlação entre as taxas de oxigenação do dedo indicador e dos dentes traumatizados e entre os dentes controle e os dentes traumatizados. Comparando-se as leituras obtidas neste estudo pode-se afirmar que taxas de oxigenação obtidas nos dentes traumatizados são confiáveis, permitindo ainda um monitoramento da condição pulpar ao longo do tempo. / The evaluation of pulp vitality depends on diagnosis methods. The most widely used are thermal and electric stimulation. However, thermal and electric testing has limitations in providing accurate diagnosis. These tests are subjective and depend upon perceived response of the patient to a stimulus, as well as the interpretation of that response by the dentist. The limitations with present pulp testing methods are that they only indirectly monitor pulp vitality by measuring neural responses and not circulation. For traumatized teeth, the pulp can be affected in a variety of ways as a function of the severity of the injury therefore, that teeth may not respond to vitality test and establishing an accurate and expedient diagnosis is even more complicated. Pulse oximetry is a completely objective test, requiring no sub jective response from the patient and directly measures the blood oxygen levels. This present study purpose was to evaluate the efficiency of pulse oximetry for testing pulp vitality by establishing correlation parameters between blood oxygen levels from the patient’s index finger, positive control teeth and traumatized permanent teeth which do not respond positively to thermal test with refrigerant spray and do not show any other sign or symptom of mortification. The results showed that there was no statistical significance between blood oxygen levels from traumatized teeth at the three different measure times (initial, 30 and 60 days) and there was a correlation between blood oxygen levels from index finger and the traumatized teeth and control teeth and traumatized teeth.

Background: Physiological studies have shown that many preterm infants and infants with chronic lung disease may suffer chronic hypoxaemia, which possibly leads to poor growth and development. Anecdotal reports indicate that there is a drive to increase the oxygen saturation target range to a higher level in these infants due primarily to perceived benefits derived from clinical experience and from uncontrolled observational studies of babies discharged on home oxygen. Objective The BOOST (Benefits Of Oxygen Saturation Targeting) trial is the first randomised trial to assess the long-term benefits and harms of two different oxygen saturation target ranges. Methods: BOOST was a multicentre, double blinded, randomised controlled trial that enrolled 358 infants born at less than 30 weeks� gestation who remained oxygen-dependent at 32 weeks postmenstrual age. They were randomly assigned to target either a functional oxygen saturation range of 91-94% (standard or control group) or 95-98% (higher or treatment group). The primary outcomes were growth and neurodevelopmental measures at 12 months corrected age. Secondary outcomes included length of hospital stay, retinopathy of prematurity, health service utilisation, parental stress, and infant temperament. Results: Prognostic baseline characteristics did not differ between the two groups. Mean birth weight and gestational age of enrolled infants was 917g and 26.5 weeks respectively. The rate of antenatal corticosteroid use was 83%.

Simultaneous blood perfusion and oxygenation monitoring is crucial for patients undergoing a transplant procedure. This becomes of great importance during the surgical recovery period of a transplant procedure when uncorrected loss of perfusion or reduction in oxygen saturation can result in patient death. Pulse oximeters are standard monitoring devices which are used to obtain the perfusion level and oxygen saturation using the optical absorption properties of hemoglobin. However, in cases of varying perfusion due to hemorrhage, blood clot or acute blockage, the oxygenation results obtained from traditional pulse oximeters are erroneous due to a sudden drop in signal strength. The long term goal of the project is to devise an implantable optical sensor which is able to perform better than the traditional pulse oximeters with changing perfusion and function as a local warning for sudden blood perfusion and oxygenation loss. In this work, an optical sensor based on a pulse oximeter with an additional source at 810nm wavelength has been developed for in situ monitoring of transplant organs. An algorithm has been designed to separate perfusion and oxygenation signals from the composite signal obtained from the three source pulse oximetry-based sensor. The algorithm uses 810nm reference signals and an adaptive filtering routine to separate the two signals which occur at the same frequency. The algorithm is initially applied to model data and its effectiveness is further tested using in vitro and in vivo data sets to quantify its ability to separate the signals of interest. The entire process is done in real time in conjunction with the autocorrelation-based time domain technique. This time domain technique uses digital filtering and autocorrelation to extract peak height information and generate an amplitude measurement and has shown to perform better than the traditional fast Fourier transform (FFT) for semi-periodic signals, such as those derived from heart monitoring. In particular, in this paper it is shown that the two approaches produce comparable results for periodic in vitro perfusion signals. However, when used on semi periodic, simulated, perfusion signals and in vivo data generated from an optical perfusion sensor the autocorrelation approach clearly (Standard Error, SE = 0.03) outperforms the FFT-based analysis (Standard Error, SE = 0.62).